Actin mRNA localizes in the absence of protein synthesis.
Actin mRNA is localized in chicken embryo fibroblasts to the distal regions of leading lamellae, but not within the ruffling edges. In this investigation we have addressed the role of actin translation in this process. The translocation of actin mRNA to the cell periphery was studied by monitoring the distribution of actin mRNA in cells during spreading. Within 90 min, actin mRNA moved from a perinuclear to a peripheral distribution. Formation of lamellipodia preceded actin mRNA localization, indicating that localization is not a prerequisite for this event. Neither puromycin (which dissociates ribosomes from mRNA) nor cycloheximide (which stabilizes ribosomes on mRNA) had any effect on this movement of actin mRNA. Anchoring of actin mRNA was studied using cells with peripherally localized actin mRNA. No change in actin mRNA localization was observed for 30 min in the same inhibitors. These data indicate that the presence of the nascent polypeptide is not necessary for translocation of actin mRNA to the cell periphery, or anchoring at that site. This suggests that the mRNA contains information concerning its spatial distribution within the cytoplasm.
Sundell
C L
CL
Department of Cell Biology, University of Massachusetts Medical School, Worcester 01655.
Singer
R H
RH
D000199:Actins / Q000235:genetics*; D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D003513:Cycloheximide / Q000494:pharmacology; D015342:DNA Probes; D004640:Emetine / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism; D007700:Kinetics; D009132:Muscles / Q000378:metabolism; D009693:Nucleic Acid Hybridization; D014176:Protein Biosynthesis / Q000187:drug effects; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*; D011691:Puromycin / Q000494:pharmacology; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D012969:Sodium Fluoride / Q000494:pharmacology
D000199:Actins; D015342:DNA Probes; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D011691:Puromycin; D012969:Sodium Fluoride; D003513:Cycloheximide; D004640:Emetine